Apache VCL versions 2.1 through 2.5 do not properly validate form input when adding and removing VMs to and from hosts. The form data is then used in SQL statements. This allows for an SQL injection attack. Access to this portion of a VCL system requires admin level rights. Other layers of security seem to protect against malicious attack. However, all VCL systems running versions earlier than 2.5.1 should be upgraded or patched. This vulnerability was found and reported to the Apache VCL project by ADLab of Venustech.
The product constructs all or part of an SQL command using externally-influenced input from an upstream component, but it does not neutralize or incorrectly neutralizes special elements that could modify the intended SQL command when it is sent to a downstream component. Without sufficient removal or quoting of SQL syntax in user-controllable inputs, the generated SQL query can cause those inputs to be interpreted as SQL instead of ordinary user data.